1. Field of the Invention
The invention relates to a method for exchanging data between a first and a second communications devices utilized in a communications system.
2. Description of the Related Art
A communications system operating at a millimeter wave (mmWave) band has a number of advantages. For example, the mmWave band is cleaner because there is less interference. A mmWave channel is capable of providing high bandwidth, of up to a gigabit per second. The challenges for a communications system when operating at an mmWave band, however, include that the radiation pattern of signals is highly directional and the medium has higher attenuation rate.
Broadband mmWave wireless communications systems may potentially be used for high bandwidth communications. However, it is crucial for the design of a broadband mmWave wireless communications system to attain and maintain as high a channel rate as possible when the mmWave band is impaired by interferences or multi-path channel fading. To address the directionality and attenuation of radio signals at the mmWave band, beamforming is a technique used to improve the reach and integrity of signals. To perform beamforming, a communications device operating at the mmWave band is embedded with an antenna array. An antenna array consists of a plurality of antennas spaced according to a predefined pattern. By applying a predetermined antenna weighting vector (AWV) to an antenna array, the radiation pattern of the signal is shaped and points toward a predetermined direction.
Another technique used in mmWave wireless communications systems is orthogonal frequency-division multiplexing (OFDM). Specifically, OFDM is used as the modulation scheme for signals. The OFDM scheme divides a broadband channel into a plurality of sub-carriers. Data transmitted over the mmWave channel are encoded, distributed to a plurality of sub-carriers, modulated according to a predetermined modulation scheme, and transmitted over the air to a receiving communications device.
Generally, interference affects a portion of the plurality of sub-carriers of a channel, thereby resulting in an increase in transmitted data errors. While mitigation methods may be used to reduce the transmitted data errors, the methods also reduce channel bandwidth capacity. As a result, an error mitigation method that minimizes the effect to the channel bandwidth is desired.